In modern distributed computer systems, a variety of computing resources are interconnected via a shared communication link. Such links typically comprise local or wide area networks on which computers may transfer information or documents between themselves as well as with shared resources such as printers or modems. Most currently utilized network schemes employ a common data bus whereby each user on the network has equal access to the bus at any given time.
One of the most often used protocols for a common bus network is referred to as carrier sense multiple-access/collision-detection (CSMA/CD). One implementation of this standard is called "Ethernet" and was developed by the Xerox Corporation. On an Ethernet network, each user transmits and receives packets of information that contain the identities of the recipient and the sender as well as the data to be transmitted. To send data on the network, each user waits until no activity is seen on the network and begins sending a message packet. While the packet is being transmitted, the user simultaneously checks for collisions, and as long as no collisions occur, continues sending the message packet. If a user detects a collision, the user intentionally jams the network to ensure that all other users see a collision and then wait a random length of time before attempting another transmission.
While equal access network protocols work well for non-priority computing applications such as e-mails or printing, etc., such protocols hinder the ability of computers to run newly developed, high bandwidth applications such as real-time audio and video. In the past, if a user on a network required increased bandwidth, a dedicated communication link had to be installed. These additional links are not cost effective and add to the maintenance needs of the network.
Given the shortcomings of prior art networking schemes, there is a need for a network communication system that can accommodate occasional high bandwidth users on the existing network without requiring additional hardware or cabling.